Simple Blockchain Implementation in Python

This project demonstrates a basic blockchain implementation using Python and Flask. The blockchain supports mining new blocks, adding transactions, and viewing the blockchain.

Features

• Mine Blocks: Generate new blocks by solving a proof of work algorithm.
• Add Transactions: Create new transactions that will be added to the next mined block.
• View Blockchain: Retrieve the full blockchain and pending transactions.
• Register Nodes: Add new nodes to the network.

Requirements

• Python 3.11 or higher
• Flask

Installation

1. Clone the repository:

   git clone https://github.com/javeria2108/Blockchain-project-in-python.git
   cd Blockchain-project-in-python

2. Create a virtual environment and activate it:

   python -m venv venv
   source venv/bin/activate  # On Windows, use `venv\Scripts\activate`

3. Install dependencies:

   pip install Flask

Usage

1. Run the Flask application:

   python app.py

2. API Endpoints:

   • Mine Block

     • URL: /mine_block
     • Method: GET
     • Description: Mines a new block and adds it to the blockchain.
     • Response: Details of the mined block.

     {
         "message": "A block is MINED",
         "index": 2,
         "timestamp": 1625074762.851,
         "proof": 35293,
         "previous_hash": "abc123...",
         "transactions": [{"sender": "sender", "recipient": "node_identifier", "amount": "10BTC"}]
     }

   • Create Transaction

     • URL: /transactions/new
     • Method: POST
     • Description: Adds a new transaction to the list of pending transactions.
     • Body: JSON containing sender, recipient, and amount.
     • Response: Confirmation message.

     {
         "message": "Transaction will be added to next Block"
     }

   • View Blockchain

     • URL: /get_chain
     • Method: GET
     • Description: Retrieves the current blockchain and pending transactions.
     • Response: The full blockchain and pending transactions.

     {
         "chain": [...],
         "pending_transactions": [...],
         "length": 1
     }

   • Register Nodes

     • URL: /nodes/register
     • Method: POST
     • Description: Registers new nodes to the blockchain network.
     • Body: JSON containing nodes (list of node addresses).
     • Response: Confirmation message.

     {
         "message": "New nodes have been added",
         "total_nodes": [...]
     }

Code Overview

Blockchain Class

• __init__: Initializes the blockchain with the genesis block.
• new_block: Creates a new block and adds it to the chain.
• last_block: Returns the last block in the chain.
• new_transaction: Adds a new transaction to the list of pending transactions.
• hash: Hashes a block.
• proof: Proof of work algorithm.

Flask Endpoints

• /mine_block: Mines a new block.
• /transactions/new: Creates a new transaction.
• /get_chain: Returns the blockchain.
• /nodes/register: Registers new nodes.